In this paper, a new method for modeling converterbased power generators in ac-distributed systems is proposed. It is
based on the concept of electrostatic synchronous machines. With this new concept, it is possible to establish a simple relationship between the dc and ac side and to study stability in both the small and large signals of the microgrid by considering a dc-link dynamic
and high variation in the power supplied. Also, for the purpose of illustration, a mathematical and electrical simulation is presented, based on MATLAB and PSCAD software. Finally, an experimental
test is performed in order to validate the new model.
This paper develops and analyzes an online methodology to detect demagnetization faults in surface-mounted permanent magnet synchronous motors. The proposed methodology, which takes into account the effect of the inverter that feeds the machine, is based on monitoring the zero-sequence voltage component of the stator phase voltages. The theoretical basis of the proposed method has been established. Attributes of the method presented here include simplicity, very low computational burden, and high sensibility. Since the proposed method requires access to the neutral point of the stator windings, it is especially useful when dealing with fault tolerant systems. A simple expression of the zero-sequence voltage component is deduced, which is proposed as a fault indicator parameter. Both simulation and experimental results presented in this paper show the potential of the proposed method to provide helpful and reliable data to carry out an online diagnosis of demagnetization failures in the rotor permanent magnets.
Garcia, A.; Rosero, J.; Cusido, J.; Romeral, L.; Ortega, J.A. IEEE transactions on energy conversion Vol. 25, num. 2, p. 312-318 DOI: 10.1109/TEC.2009.2037922 Data de publicació: 2010-06 Article en revista
This paper presents a novel method to diagnose demagnetization
in permanent-magnet synchronousmotor (PMSM).
Simulations have been performed by 2-D finite-element analysis in
order to determine the current spectrum and the magnetic flux
distribution due to this failure. The diagnostic just based on motor
current signature analysis can be confused by eccentricity failure
because the harmonic content is the same. Moreover, it can
only be applied under stationary conditions. In order to overcome
these drawbacks, a novel method is used based upon the
Hilbert–Huang transform. It represents time-dependent series in a
2-D time–frequency domain by extracting instantaneous frequency
components through an empirical-mode decomposition process.
This tool is applied by running the motor under nonstationary
conditions of velocity. The experimental results show the reliability
and feasibility of the methodology in order to diagnose the demagnetization
of a PMSM.